Systems, apparatuses, and methods for protecting electronic components from high power noise induced by high voltage pulses

ABSTRACT

Systems, devices, and methods for electroporation ablation therapy are disclosed, with a protection device for isolating electronic circuitry, devices, and/or other components from a set of electrodes during a cardiac ablation procedure. A system can include a first set of electrodes disposable near cardiac tissue of a heart and a second set of electrodes disposable in contact with patient anatomy. The system can further include a signal generator configured to generate a pulse waveform, where the signal generator coupled to the first set of electrodes and configured to repeatedly deliver the pulse waveform to the first set of electrodes. The system can further include a protection device configured to selectively couple and decouple an electronic device to the second set of electrodes.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Patent Application No. PCT/US2020/061564, filed on Nov. 20, 2020, which is a continuation-in part of U.S. patent application Ser. No. 16/689,967, filed on Nov. 20, 2019. This application is also a continuation-in-part of U.S. patent application Ser. No. 16/689,967. The entire disclosures of each of the above-referenced applications are incorporated herein by reference in their entirety.

TECHNICAL FIELD

The embodiments described herein relate generally to medical devices for therapeutic electrical energy delivery, and more particularly to systems, apparatuses, and methods for protecting electronic components (e.g., sensitive equipment or circuitry) during pulsed electric field ablation procedures.

BACKGROUND

Application of brief ultra-short high voltage pulses to tissue may generate high electric fields in tissue to generate a local region of ablated tissue by the biophysical mechanism of irreversible electroporation. In applications including cardiac applications, high voltage pulses may be applied in synchrony with a cardiac cycle of a subject. For example, high voltage pulses can be applied during specific periods of the cardiac cycle (e.g., refractory cycle of the cardiac chambers), thereby avoiding the risk of induced arrhythmias such as ventricular fibrillation. In some applications, to ensure synchrony of pulsed field ablation pulses with the cardiac cycle, a cardiac stimulator can be used to pace or stimulate the cardiac chamber(s) with a regular cycle of periodic pacing signals having a well-defined time period to establish periodicity of electrocardiogram (ECG) activity of the heart. Other devices, e.g., sensing and/or mapping systems, monitoring equipment or devices, can also be used to monitor a subject's cardiac cycle or detail a subject's cardiac activity. A cardiac stimulator may also be used in clinical procedures where a pacing function is required to maintain periodic and regular electrical activity in the cardiac chambers during at least a portion of the procedure. The cardiac stimulator and these other devices can use intracardiac devices (e.g., catheters) that can be suitably positioned in one or more cardiac chamber(s) to deliver signals to or receive signals from the heart, or external surface patches or surface leads to record patient surface ECG recordings. When these devices are used during a pulsed electric field ablation procedure, however, they can become exposed to high voltages. Such exposure can result in large, generally unbalanced, currents, and/or large common mode voltages with respect to earth ground, being induced in the electrodes or leads of the intracardiac catheters. The large unbalanced currents and/or voltages can span a band of frequencies and disrupt the operation of the cardiac stimulator and/or these other devices, thus interrupting pacing, sensing, mapping, magnetic sensor operation, and/or pulsed field ablation functions. The disruption may be due to a hardware response to the voltages and currents, or due to the equipment actively monitoring the patient for anomalous signals for safety reasons.

Accordingly, it can be desirable to have systems, apparatuses, and methods for addressing this issue.

SUMMARY

Described herein are systems, devices, and methods for protecting electronic components (e.g., circuitry, devices, and/or other components) from induced currents and high voltage exposure during pulsed electric field ablation procedures.

In some embodiments, the ablation devices used in these systems may be deployed epicardially or endocardially in cardiac applications. The pulse waveforms delivered by the ablation devices may include predetermined parameters or may be automatically generated by a signal generator.

In some embodiments, a system can include a first set of electrodes and a second set of electrodes. Generally, the second set of electrodes can be disposed near cardiac tissue of a heart, or they can be part of surface patches or similar external recording or monitoring devices. A signal generator may be configured to generate a pulse waveform. The signal generator may be coupled to the first set of electrodes and in some embodiments can be configured to repeatedly deliver the pulse waveform to the first set of electrodes in synchrony with a set of cardiac cycles of the heart. In other embodiments, the signal generator can be configured to repeatedly deliver the pulse waveform to the first set of electrodes without synchrony being established with the cardiac cycle. In this latter case, it can still be useful to protect other electronic components (e.g., lab equipment such as cardiac stimulators (used generally for pacing functions), mapping systems, magnetic tracking equipment, imaging equipment, etc.). The first set of electrodes may be configured to generate a pulsed electric field in response to the delivery of the pulse waveform to ablate the cardiac tissue. A protection device may be configured to selectively couple and decouple an electronic device to the second set of the electrodes. A control element (e.g., processor, switch, control signal) may be coupled to the protection device and configured to control the protection device to decouple the electronic device from the second set of electrodes during intervals of time beginning before and ending after each delivery of the pulse waveform to the first set of electrodes.

In some embodiments, an apparatus may include a first set of electrodes disposable near cardiac tissue of a heart. A signal generator may be coupled to the first set of electrodes and configured to generate a pulse waveform. A switch component may be coupled to the signal generator. The switch component may be configured to switch between a conducting state in which an electronic device is coupled to a second set of electrodes and a non-conducting state in which an electronic device is decoupled from the second set of electrodes. The second set of electrodes may be disposable near the first set of electrodes, or generally in a cardiac or anatomical chamber, or it may be disposed on or near the external surface of the subject. A processor may be coupled to the switch component. The processor may be configured to receive trigger signals, each trigger signal associated with a cardiac cycle of the heart or with an ablation output from the signal generator. In response to receiving each trigger signal, the processor may be configured to set the switch component to the non-conducting state such that the electronic device is decoupled from the second set of electrodes. The processor may be configured to deliver, from the signal generator and after setting the switch component to the non-conducting state, the pulse waveform to the first set of electrodes such that the first set of electrodes generates a pulsed electric field. The processor may be configured to set, after delivering the pulse waveform, the switch component to the conducting state such that the electronic device is coupled to the second set of electrodes. In some embodiments, a control signal being coupled to the switch component can set the state of the switch to perform the functions described above.

In some embodiments, a method may include delivering pacing signals to a heart by a second set of electrodes positioned near cardiac tissue of the heart. After delivery of each pacing signal to the heart, the switch component being selectively able to couple to an electronic device may be set to be in a non-conductive state such that the second set of electrodes is decoupled from the electronic device. After setting the switch component to be in the non-conductive state, a pulse waveform may be delivered to a first set of electrodes positioned near cardiac tissue of the heart such that the first set of electrodes generates a pulsed electric field for ablating the cardiac tissue. After delivering the pulse waveform, the switch component may be set to be in a conductive state such that the second set of electrodes is coupled to the electronic device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of components of a signal generator and a cardiac stimulator being disposed in a heart, according to embodiments.

FIG. 2 is a schematic diagram of components of a signal generator and a cardiac stimulator being disposed in a heart, with passive filtering for protection of the cardiac stimulator, according to embodiments.

FIG. 3A is a schematic diagram of a system for protecting electronic components from high voltage signals, according to embodiments.

FIG. 3B is a schematic diagram of a system for protecting electronic components from high voltage signals, according to embodiments, including externally and/or internally disposed electrodes that may be connected to a variety of medical equipment, including but not limited to cardiac stimulators, ECG recording systems, ECG or other patient data monitoring systems, electroanatomical mapping systems, device navigation/tracking systems, other monitoring systems and devices, combinations thereof, and the like.

FIG. 4 is a schematic diagram of components of a signal generator and one or more pieces of medical electronic equipment connected to electrodes disposed in a heart/cardiac anatomy or on a patient surface, with a protection device for protection of the medical electronic equipment, according to embodiments.

FIG. 5 is a circuit diagram of a protection device for protecting electronic components from high voltage signals, according to embodiments.

FIG. 6A illustrates a method for protecting electronic components from high voltage signals, according to embodiments.

FIG. 6B illustrates a method for protecting electronic components from high voltage signals for asynchronous delivery of ablation, according to embodiments.

FIG. 7A illustrates a time sequence of a cardiac pacing signal, energy delivery, and device isolation, according to embodiments. FIG. 7B illustrates a time sequence of a cardiac pacing signal, cardiac activity, energy delivery, and device isolation, according to embodiments.

FIG. 8 is a schematic diagram of a system for protecting electrical components from high voltage signals, according to embodiments.

FIG. 9 illustrates a time sequence of a cardiac pacing signal, cardiac activity, energy delivery, and device isolation, according to embodiments.

FIGS. 10A-10E are block diagrams of alternative arrangements of a protection device and a high voltage generator, according to embodiments.

FIG. 11 is a schematic diagram of a protection device for controlling connections between electronic components operating in a high voltage exposure area, according to embodiments.

FIG. 12 is a schematic diagram of a system for protecting electronic components from high voltage signals, according to embodiments.

FIG. 13 illustrates a time sequence of a cardiac pacing signal, cardiac activity, energy delivery, and device isolation, according to embodiments.

FIG. 14 is a schematic diagram of a protection device for controlling connections between electronic components operating in a high voltage exposure area, according to embodiments.

FIG. 15 is a schematic diagram of a protection device for controlling connections between electronic components operating in a high voltage exposure area, according to embodiments.

FIG. 16 is a schematic diagram of a protection device for controlling connections between electronic components operating in a high voltage exposure area, according to embodiments.

FIGS. 17A and 17B illustrate time sequences of a cardiac pacing signal, cardiac activity, energy delivery, and device isolation, according to embodiments.

FIG. 18 is a schematic diagram of a protection device for controlling connections between electronic components operating in a high voltage exposure area, according to embodiments.

FIG. 19 is a schematic diagram of a system for protecting electrical components from high voltage signals, according to embodiments.

FIG. 20A is a illustrates a time sequence of a signal connection and energy delivery, according to embodiments.

FIG. 20B is a illustrates a time sequence of a signal connection and energy delivery, according to embodiments.

FIG. 20C is a illustrates a time sequence of a signal connection and energy delivery, according to embodiments.

DETAILED DESCRIPTION

Described herein are systems, devices, and methods for protecting circuits from high power noise induced during pulsed electric field ablation. Pulsed electric field ablation uses ultra-short high-voltage pulses to generate large electric fields at desired regions of interest to generate a local region of ablated tissue via irreversible electroporation. In certain applications, including cardiac applications, it can be desirable to generate pulses for pulsed electric field ablation in synchronicity with a cardiac cycle. Synchronizing ablation energy delivery with the cardiac cycle may reduce the risk of induced arrhythmias such as atrial and/or ventricular fibrillation. One method of synchronizing delivery of pulses can be to pace or stimulate one or more cardiac chambers with periodic pacing signals with a predefined time period. For example, a cardiac stimulator may be used to deliver pacing pulses to one or more cardiac chambers such that the cardiac rhythm of a patient synchronizes with the pacing pulse.

In some embodiments, pacing pulses can be delivered to the cardiac chamber(s) via an intracardiac catheter that is suitably positioned in the chamber(s). For example, FIG. 1 depicts a cardiac stimulator (28) that is coupled to an intracardiac catheter (30) suitable positioned in a chamber of a heart (2). The catheter (30) can have one or more electrodes (32, 34) that are used to conduct a pacing signal into the heart. In an embodiment, a pair of electrodes on the catheter (30) (e.g., a most distal electrode (32) and an electrode (34) immediately proximal to the most distal electrode (32)) can be used as a bipolar pair to deliver the pacing signal, thus providing forward and return current paths for the pacing signal. The cardiac chamber responds to the pacing pulse (referred to herein as “pacing capture”) by timing its ECG signal generation (e.g., the QRS waveform) to synchronize with the pacing pulse. Accordingly, periodicity of the ECG activity of the heart can be established. Once such periodicity is established and confirmed by the physician (e.g., from displayed ECG activity obtained, for example, for a variety of recording or sensing electrodes), the delivery of the pulsed field ablation pulses can be timed to start in synchrony with the pacing pulses, including any predetermined offsets, and delivery can be completed within refractory windows following the QRS waveform of an ECG signal.

In cardiac applications, pulsed field ablation energy can be delivered through a customized ablation catheter including a plurality of electrodes. For example, as depicted in FIG. 1, a signal generator (22) (e.g., a pulsed field ablation pulse generator) can be coupled to an ablation catheter (10) with electrodes (12) that are suitably disposed in the heart (2). The delivery of the pulsed field ablation voltage pulses can be synchronized with the delivery of the pacing signals with appropriate offsets, as indicated by (60). Since the pacing catheter (30) can be located in the cardiac environment as well (e.g., in the same or a nearby chamber of the heart (2)), high voltage pulse waveforms applied to heart tissue may couple to the pacing catheter (30) and induce currents in one or more of the pacing catheter (30) and devices coupled thereto (e.g., cardiac stimulator (28)).

During normal delivery of pacing pulses, the forward and return currents of the electrodes (32, 34) of the pacing catheter (30) are balanced (e.g., equal in magnitude and opposite in direction). However, electrical coupling of the high voltage ablation energy to the pacing catheter (30) may induce large and generally unbalanced currents and/or common mode voltages in the leads of the pacing catheter (30). These large unbalanced currents and/or voltages can span a band of frequencies and can disrupt the operation of the pacing system or cardiac stimulator (28) or other electronic equipment coupled thereto. For example, the large voltage exposure of the pacing catheter (30) may exceed the common-mode rejection of the cardiac stimulator (28) and cause system failure and/or reset of the stimulator (which can be either pacing for synchronized delivery of ablation or pacing the cardiac chamber(s) for other medical reasons). The high voltage levels and high currents associated with the induced noise imply a large power level for the noise and can lead to unwanted effects.

This high-power induced noise can be difficult to suppress and, therefore, it can be desirable to have systems, devices, and methods for suppressing induced currents in accessory devices in pulsed electric field ablation energy delivery applications. In some embodiments, currents induced by pulsed electric field ablation can be suppressed through implementation of passive filtering systems, devices, and methods, as described in U.S. application Ser. No. 62/667,887, filed on May 7, 2018, and titled “SYSTEMS, APPARATUSES, AND METHODS FOR FILTERING HIGH VOLTAGE NOISE INDUCED BY PULSED ELECTRIC FIELD ABLATION,” the contents of which are hereby incorporated by reference in its entirety. FIG. 2 depicts an example of a system including passive filtering. A cardiac stimulator (28′) can be coupled to a pacing catheter (30′) including a plurality of electrodes (32′, 34′). A signal generator (22′) can be coupled to an ablation catheter (10′) including a plurality of electrodes (12′). The electrodes (32′, 34′) of the pacing catheter (30′) can be disposed in a heart (2′) along with the electrodes (12′) of the ablation catheter (10′). A filter element (50′) can be coupled between the cardiac stimulator (28′) and the pacing catheter (30′). The filter element (50′) can passively filter signals from the pacing catheter (30′) prior to those signals being received at the cardiac stimulator (28′), thereby suppressing certain induced currents. For example, at A, long wires can pick up high voltages, while at B, after the passive filtering, residual voltage and current can pass onto the cardiac stimulator (28′).

In some instances, however, coupled noise having a large amplitude (e.g., large voltage spikes) can be difficult to reject using passive filtering techniques and therefore faults and/or resets of equipment including a cardiac stimulator can still occur. Commercially available stimulators can also include different design parameters such that one level of protection may be sufficient for one type of stimulator while being insufficient for a second type of stimulator.

Systems, devices, and methods disclosed herein provide protection for sensitive electronics and ancillary devices in pulsed electric field ablation applications using actively driven rapid switching of signal paths. In some embodiments, a protection device may be coupled to the pacing device to actively and selectively electrically isolate the pacing device from the other electronic components of the ablation system. In particular, the pacing device may be electrically isolated from the system during a predetermined time period corresponding to delivery of the pulse waveform to tissue. Electrical connection may be reestablished to enable operation of the pacing device between periods of high voltage energy delivery. In some embodiments, the protection device may include a high speed switch coupled between the ablation system and pacing device. Consequently, components of the system such as the cardiac stimulator may be protected from currents that may be induced in the pacing device by the high voltage pulse waveforms applied by the ablation device. Additionally or alternatively, the protection device may further provide passive circuit protection.

In some embodiments, sensitive circuitry or a piece of ancillary equipment (e.g., a cardiac stimulator, electroanatomical mapping system, ECG recording or monitoring system, etc.) can be protected from high voltage pulsed field ablation signals present in a subject by having such circuitry or equipment be electrically isolated. Electrical isolation can be implemented manually by disconnecting conductors between the circuitry or equipment can the subject, but a manual approach may not be possible in certain instances. For example, for certain types of equipment that serve repeated function, e.g., a cardiac stimulator that is intended to provide ongoing pacing of a subject's heart during a pulsed field ablation procedure, it is necessary for physical connections between the equipment and the subject to remain intact. In these instances, it can be desirable to accomplish physical disconnection using electronic components. For example, electronic components can be used to provide bi-directional open circuit isolation between the subject and protected ancillary equipment for certain time intervals during which a high voltage is present and re-establish connections during other time intervals to otherwise allow for intended functioning of the equipment.

The term “electroporation” as used herein refers to the application of an electric field to a cell membrane to change the permeability of the cell membrane to the extracellular environment. The term “reversible electroporation” as used herein refers to the application of an electric field to a cell membrane to temporarily change the permeability of the cell membrane to the extracellular environment. For example, a cell undergoing reversible electroporation can observe the temporary and/or intermittent formation of one or more pores in its cell membrane that close up upon removal of the electric field. The term “irreversible electroporation” as used herein refers to the application of an electric field to a cell membrane to permanently change the permeability of the cell membrane to the extracellular environment. For example, a cell undergoing irreversible electroporation can observe the formation of one or more pores in its cell membrane that persist upon removal of the electric field.

Pulse waveforms for electroporation energy delivery as disclosed herein may enhance the safety, efficiency, and effectiveness of energy delivery to tissue by reducing the electric field threshold associated with irreversible electroporation, thus yielding more effective ablative lesions with a reduction in total energy delivered. In some embodiments, the voltage pulse waveforms disclosed herein may be hierarchical and have a nested structure. For example, the pulse waveform may include hierarchical groupings of pulses having associated timescales. In some embodiments, the methods, systems, and devices disclosed herein may comprise one or more of the methods, systems, and devices described in International Application Serial No. PCT/US2019/014226, filed on Jan. 18, 2019, published as International Publication No. WO/2019/143960 on Jul. 25, 2019, and titled “SYSTEMS, DEVICES AND METHODS FOR FOCAL ABLATION,” the contents of which are hereby incorporated by reference in its entirety.

Systems and Devices

Disclosed herein are systems and devices configured for suppressing induced currents in connection with tissue ablation. Generally, a system described here for ablating tissue with high voltage pulse waveforms may include a cardiac stimulator for generating a cardiac pacing signal delivered by a pacing device to the heart. The cardiac pacing signal is used to synchronize delivery of a pulse waveform generated by a signal generator, and the pulse waveform is delivered using an ablation device having one or more electrodes. In another embodiment, the ablation with high voltage pulse waveforms can be performed asynchronously (i.e., without synchronizing with cardiac stimulation). It is generally desirable in these embodiments also to protect other electronic equipment such as cardiac stimulators, electroanatomical mapping systems, device navigation/tracking systems, ECG recording or monitoring systems etc. that may be connected to the patient via device electrodes that are placed either internally in the patient or externally on the patient or attached to the patient surface (for example, needle electrodes, pacing leads etc.). Thus, the systems, methods and implementations described in the present disclosure apply to asynchronous ablation delivery. Furthermore, as described herein, the systems and devices may be deployed epicardially and/or endocardially to treat atrial fibrillation. Voltages may be applied to a selected subset of the electrodes, with independent subset selections for anode and cathode electrode selections.

FIG. 3A illustrates an example system (1700) including an integrated protection element (1750). The protection element (1750) can be situated between electrical components (1730) and a target area (TA) (e.g., a heart of a patient). The protection element (1750) can be configured with a voltage rating corresponding to an anticipated exposure voltage on the patient side of a pulsed electric field ablation procedure, which can be a few thousand volts. The protection element (1750) can function as an isolation component that is configured to transition to an open circuit configuration and back to a closed circuit configuration based on a control signal. The protection element (1750) is configured to respond quickly (e.g., quickly switch between its open and closed configurations) to reduce the open-circuit duty cycle, such that the protection element (1750) can electrically isolate certain electrical components (1730) (e.g., monitoring equipment or devices, cardiac stimulators, etc.) for the duration of a high-voltage exposure but otherwise connect those electrical components to the target area (TA).

Examples of suitable protection elements (1750) include electro-mechanical relays (e.g., reed relays), solid-state relays, and/or high-voltage metal-oxide semiconductor field-effect transistor (MOSFET) devices. Reed relays can be a less suitable option for isolation component implementation, as such relays act slower than other types of protection devices and are susceptible to damage/contact fusing if switched during exposure to high currents. When the system (1700) is used with the protection element (1750) implemented as a reed relay, the coordination and timing of the system (1700) need to be adjusted to handle the slower reaction time of such relays. A preferred implementation of a protection element (1750) is with two back-to-back MOSFETs with common source terminals, as further described with reference to FIG. 5 below.

FIG. 3B illustrates an example system (1800) including an integrated protection element (1805). The protection element (1805) can be situated between electrical components (1801) and patient anatomy (1808). The protection element (1805) can be configured with a voltage rating corresponding to an anticipated exposure voltage on the patient side of a pulsed electric field ablation procedure, which can be a few thousand volts. Such high voltage exposure can occur via internally placed (with respect to patient) device electrodes or sensors (1819) or externally placed/mounted (on the patient surface) electrodes or sensors (1821). Such electrodes or sensors in general can connect to a variety of medical electronic equipment, including but not limited to electroanatomical mapping systems, device navigation/tracking systems, ECG recording/monitoring systems, combinations thereof, and the like that can generally be in use in a clinical laboratory or procedure room. In the embodiments described herein, a sensor can be a generic sensor including a dedicated electromagnetic sensor, an electrode for receiving voltage signals generated by a location tracking system, an electrode for monitoring native cardiac electrical activity, and more generally a sensor for sensing electrical signals of various types. The protection element (1805) can function as an isolation component that is configured to transition to an open circuit configuration and back to a closed circuit configuration based on a control signal (1812). The protection element (1805) is configured to respond quickly (e.g., quickly switch between its open and closed configurations) to reduce the open-circuit duty cycle, such that the protection element (1805) can electrically isolate electrical components (1801) such as those described above for the duration of a high-voltage exposure but otherwise connect those electrical components to the patient anatomy (1808).

Examples of suitable protection elements (1805) include electro-mechanical relays (e.g., reed relays), solid-state relays, and/or high-voltage metal-oxide semiconductor field-effect transistor (MOSFET) devices. Reed relays can be a less suitable option for isolation component implementation, as such relays act slower than other types of protection devices and are susceptible to damage/contact fusing if switched during exposure to high currents. When the system (1800) is used with the protection element (1805) implemented as a reed relay, the coordination and timing of the system (1800) need to be adjusted to handle the slower reaction time of such relays. In some embodiments, a protection element (1805) can include two back-to-back MOSFETs with common source terminals, as further described with reference to FIG. 5 below.

FIG. 4 is a schematic diagram of an electroporation system disposed in a heart (202) of a patient (200). The electroporation system may include an ablation device (210), signal generator (222), electrical component(s) (e.g., medical electronic equipment or devices) (228), catheter device (230), and protection device (e.g., protection circuit) (250). In some embodiments, the electrical component(s) (228) may be implemented as a cardiac pacing system. The signal generator (222) may be coupled to the ablation device (210) and configured to receive a pacing/synchronization signal (260) generated by the cardiac pacing system. The signal generator (222) may be configured to generate ablation pulse waveforms delivered to tissue by electrodes (212) of the ablation device (210). In some embodiments, the catheter device (230) implemented as a pacing device (230) may be configured to pace the heart and measure cardiac activity using respective pacing electrodes (232) and signal electrodes (234). In some embodiments, the electrical component(s) (228) can be implemented as monitoring equipment or devices that can be coupled to one or more sensors (e.g., electrodes) (232, 234, 271) for measuring physiological data of a patient. In some embodiments, sensors (e.g., electrodes (271)) may be placed externally at the patient surface. The protection device (250) may be coupled between the electrical component(s) (228) and the electrodes (232, 234) of the catheter device (230) or electrodes (271). In some embodiments, the protection device (250) is configured to synchronize electrical isolation of the pacing device (230) with delivery of ablation energy by the ablation device (210).

In some embodiments, a distal portion of an ablation device (210) may be introduced into an endocardial space of the heart (202) (e.g., a left atrium), e.g., through an atrial septum via a trans-septal puncture. The distal portion of the ablation device (210) may include a set of electrodes (212) configured to deliver ablation energy (e.g., pulse electric field energy) to tissue. For example, the ablation device (210) may be positioned near an inner radial surface of a lumen (e.g., one or more pulmonary vein ostia) (not shown) for delivery of pulse waveforms to ablate tissue. In some embodiments, the electrodes (212) of the ablation device (216) may be a set of independently addressable electrodes. Each electrode may include an insulated electrical lead configured to sustain a voltage potential of at least about 700 V without dielectric breakdown of its corresponding insulation. In some embodiments, the insulation on each of the electrical leads may sustain an electrical potential difference of between about 200 V to about 3,000 V across its thickness without dielectric breakdown. In some embodiments, the set of electrodes may include a plurality of electrodes. The plurality of electrodes may be grouped into one or more anode-cathode subsets such as, for example, a subset including one anode and one cathode, a subset including two anodes and two cathodes, a subset including two anodes and one cathode, a subset including one anode and two cathodes, a subset including three anodes and one cathode, a subset including three anodes and two cathodes, and/or the like.

The signal generator (222) may be configured to generate ablation pulse waveforms for irreversible electroporation of tissue, such as, for example, pulmonary vein ostia. For example, the signal generator (222) may be a voltage pulse waveform generator and deliver a pulse waveform to the ablation device (210).

In some embodiments, the signal generator (222) is configured to generate the ablation pulse waveform in synchronization with the indication of the pacing signal (e.g., within a common refractory window). For example, in some embodiments, the common refractory window may start substantially immediately following a ventricular pacing signal (or after a very small delay) and last for a duration of approximately 250 milliseconds (ms) or less thereafter. In such embodiments, an entire pulse waveform may be delivered within this duration.

The protection device (250) may be coupled between the electrical components (228) and the catheter device (230). As described in more detail herein, a control signal (also referred to herein as a protection signal) may be generated to synchronize operation of the protection device (250) with the generation of the pulse waveform by the signal generator (222). The protection device (250) may be configured to receive the control signal to control a state of the electrical connection between the catheter device (230) and the electrical components (228). For example, the protection device (250) may be configured to form an open circuit between the electrical components (228) and the catheter device (230) at least during delivery of ablation energy by the ablation device (210). Otherwise, the protection device (250) may be configured to electrically couple the pacing device (230) with the electrical components (228). In some embodiments, the protection device (250) may be configured to provide bi-directional open circuit isolation during high energy ablation energy delivery. In some embodiments, the protection device (250) may be formed separate from the electrical components (228) and/or the catheter device (230), and in other embodiments, the protection device (250) can be integrated into one or more electrical components (228) and/or catheter device (230). In some embodiments, the protection device (250) may include one or more of an internal power source (e.g., battery) and a power connector to couple to an external power source (e.g., medical grade power supply, wall-outlet). An internal power source may reduce ground noise injection.

In some embodiments, the electrical components (228), the protection device (250), and/or the signal generator (220) may be in communication with one another, e.g., for coordinating timing of the pulse waveform delivery, pacing signal delivery, and/or protection device control signal delivery. In some embodiments, the protection device (250), and/or the signal generator (220) may be in communication with one another, e.g., for coordinating timing of the pulse waveform delivery, pacing signal delivery, and/or protection device control signal delivery. In some embodiments, the protection device (250) may be integrated with the signal generator (222) in a single console.

In some embodiments, the electrical components (228), the protection device (250), and/or the signal generator (220) may be in communication with other devices (not shown) via, for example, one or more networks, each of which may be any type of network. A wireless network may refer to any type of digital network that is not connected by cables of any kind. However, a wireless network may connect to a wireline network in order to interface with the Internet, other carrier voice and data networks, business networks, and personal networks. A wireline network is typically carried over copper twisted pair, coaxial cable or fiber optic cables. There are many different types of wireline networks including, wide area networks (WAN), metropolitan area networks (MAN), local area networks (LAN), campus area networks (CAN), global area networks (GAN), like the Internet, and virtual private networks (VPN). Hereinafter, network refers to any combination of combined wireless, wireline, public and private data networks that are typically interconnected through the Internet, to provide a unified networking and information access solution. The system (100) may further comprise one or more output devices such as a display, audio device, touchscreen, combinations thereof, and the like.

The electrical components (228), the protection device (250), and/or the signal generator (220) can include one or more processor(s), which can be any suitable processing device configured to run and/or execute a set of instructions or code. The processor may be, for example, a general purpose processor, a Field Programmable Gate Array (FPGA), an Application Specific Integrated Circuit (ASIC), a Digital Signal Processor (DSP), and/or the like. The processor may be configured to run and/or execute application processes and/or other modules, processes and/or functions associated with the system and/or a network associated therewith (not shown). The underlying device technologies may be provided in a variety of component types, e.g., metal-oxide semiconductor field-effect transistor (MOSFET) technologies like complementary metal-oxide semiconductor (CMOS), bipolar technologies like emitter-coupled logic (ECL), polymer technologies (e.g., silicon-conjugated polymer and metal-conjugated polymer-metal structures), mixed analog and digital, and/or the like.

The electrical components (228), the protection device (250), and/or the signal generator (220) can include one or more memory or storage device(s), which can be, for example, a random access memory (RAM), a memory buffer, a hard drive, an erasable programmable read-only memory (EPROM), an electrically erasable read-only memory (EEPROM), a read-only memory (ROM), Flash memory, etc. The memory may store instructions to cause the processor of any one of the electrical components (228), the protection device (250), and/or the signal generator (220) to execute modules, processes and/or functions, such as pulse waveform generation, isolation/protection, and/or cardiac pacing.

While FIG. 4 depicts a system including electrical components (228) that are separate from the signal generator (220), in some embodiments, one or more electrical components (228) may form a part of and/or be integrated into signal generator (222). In some embodiments, one or more electrodes (212, 232, 234) may function as sensing electrodes.

FIG. 5 is a circuit diagram of a protection device (300) including a first MOSFET (310) and a second MOSFET (320). The MOSFETs (310, 320) can be arranged as back-to-back MOSFETs with common source terminals such that the body diodes of the MOSFETs (310, 320) are in opposing directions. Such an arrangement can provide bi-directional isolation with precise timing control. The MOSFETs (310, 320) can be driven by isolated gate-drive circuits (330, 340). Specifically, the first MOSFET (310) can be coupled to a first gate driver (330), and the second MOSFET (320) can be coupled to a second gate driver (340). The first and second gate drivers (330, 340) may be coupled to a coupling (350) (e.g., an isolation/optical coupling) that can receive a control signal 352. The protection device (300) may be configured to reduce high voltage coupling of connected devices. For example, the protection device (300) may be configured to withstand voltages of up to about 3,000 V delivered by an ablation device. The protection device (300) may be configured to transition between a closed-circuit configuration and an open-circuit configuration based on a received protection signal (352) (e.g., control signal) such that the protection device (300) is in an open-circuit configuration for the duration of high-voltage ablation energy delivery and in a closed-circuit configuration at other times, e.g., to enable delivery of a pacing signal.

The protection devices described herein can be a separate piece of equipment or can be integrated into ancillary equipment or a pulsed field ablation stimulator. FIGS. 10A-10E are block diagrams of a set of systems including protection devices, both integrated with and separate from other system components. In FIGS. 10A-10E, the protection devices can include components that are structurally and/or functionally similar to any of the other protection devices described herein (e.g., protection devices depicted in FIGS. 3A, 3B, 4, 5, 8, 11, 12, 14-16, 18, and 19). FIG. 10A illustrates a signal generator (800) (e.g., for pulsed electric field ablation) comprising a protection device (810) integrated therewith. For example, one or more of the signal generator (800), protection device (810), electrical components (e.g., electrical components (228) including, for example, monitoring equipment, a cardiac stimulator, etc.), and signal analyzer (e.g., signal detector (670)) may be integrated into a single enclosure (e.g., housing, signal generator console). This may allow sensitive electronic circuitry to be protected within the same enclosure from high voltage noise. External electrical components (e.g., ancillary equipment) may be similarly protected by coupling such components to the protection device (810) at a point further downstream from the high voltage exposure point (e.g., the patient). For example, external equipment can be protected by routing signals received by the system through the protection device (810) before having those signals reach the patient, such that the protection device (810) can time its blanking interval to coincide with times of potential high voltage exposure. With the integrated configuration depicted in FIG. 10A, a digital “blanking” signal (e.g., control signal) can be provided to the protection device by the signal generator (800) to indicate the necessary time for isolation (e.g., protection) of sensitive electronic components. The “blanking” signal may be configured to control the protection device to electrically isolate a set of electronic components internal and external to the signal generator (800), thereby providing coordinated and robust protection.

In some embodiments, manually operated switches can be configured to be a protection device to protect electronic components or equipment from ablation-induced noise.

In some embodiments, the signal generator and protection device may be separate pieces of equipment (e.g., formed in different enclosures). In such embodiments, control signals can be transmitted between the signal generator and protection device via wired or wireless communications; however, wired control signals can be more robust and avoid the risk of delay more often associated with wireless communications. With an external or separate protection device, the protection device can be either battery-powered or wall-powered, e.g., using medical grade isolation, but battery-powered protection devices can be more desirable to reduce ground noise injection into the patient from isolated wall power supplies. FIG. 10B illustrates a signal generator (800) coupled to a protection device (810) via a wired connection (820) (e.g., power/data cable). FIG. 10C illustrates a signal generator (800) coupled to a protection device (810) via a wireless connection. For example, the protection device (810) may comprise a wireless transceiver (830) configured to receive a control signal (e.g., transmitted from the signal generator (800)).

In embodiments where the protection device is implemented independently from the signal generator (e.g., pulsed field ablation generator), the protection device requires a mechanism for synchronizing with delivery of high voltages pulses such that it can effectively isolate certain electronic components during such delivery. In some embodiments, a protection signal may synchronize electrical isolation of certain electronic components (e.g., a stimulator) with delivery of ablation energy to tissue based on one or more of a timed-trigger pulse from a stimulator, stimulation-pulse sensing (e.g., of stimulation pulses for cardiac capture), measured cardiac activity (e.g., R-wave detection, and/or high-voltage sensing (e.g., with rapid application of isolation upon detection of a high voltage spike on a patient side). Such is further described below with reference to FIG. 12. FIGS. 10D and 10E illustrate two configurations of implementing synchronization. Such configurations are similar to those described with respect to FIGS. 7A-9. FIG. 10D illustrates a signal generator (800) and a protection device (810), both configured to receive signals from a cardiac stimulator (840). The cardiac stimulator (840) may be configured to synchronize ablation energy delivery by the signal generator (800) and electrical isolation by the protection device (810) through output of respective signals (e.g., a trigger or control signal) to the signal generator (800) and the protection device (810). FIG. 10E illustrates a signal generator (800) and a protection device (810) both coupled to a patient (850) and configured to operate in synchronicity with one another based on measured data (e.g., cardiac stimulation or pacing pulse, R-wave detection, high voltage detection). When implementing synchronization based on stimulation pulse detection, a sufficiently high predetermined threshold (e.g. 5 V) can be set to reduce the likelihood of false-positive sensing, which can undesirably lead to increased occurrences of isolation and disconnection of protected electrical components from a patient.

Protection devices as described herein can be configured to isolate a plurality of electrical components (e.g., sensitive circuitry or equipment) from high voltages and induced currents. FIG. 11 is a block diagram of a system (910) coupled to a patient (900). One or more devices of the system (910) (e.g., pacing device, catheters, stylets, probes, electrodes, etc.) may be coupled to the patient (900) and may be susceptible to induced current from high voltage ablation energy delivery. Each of the devices of the system (910) may be coupled to a protection device (920) configured to selectively electrically isolate electrical components disposed downstream from the protection device (920) from those portions of devices disposed in the heart and are exposed to the high voltages. The protection device (920) can include components that are structurally and/or functionally similar to any of the other protection devices described herein (e.g., protection devices depicted in FIGS. 3A, 3B, 4, 5, 8, 10A-10E, 12, 14-16, 18, and 19). In some embodiments, a single protection signal (924) may be configured to control the protection device (920) and provide electrical isolation, e.g., through protection elements implemented as a plurality of switches (922), of the plurality of electronic component(s) simultaneously. In some embodiments, one or more of the switches (922) can include electro-mechanical relays (e.g., reed relays), solid-state relays, and/or MOSFET devices. For example, one or more of the switches (922) can include two back-to-back MOSFETs with common source terminals, as depicted in FIG. 5.

In some embodiments, e.g., where a protection device is implemented as an independent system without signals being communicated from a high voltage pulse generator (e.g., for pulsed field ablation), the operation of the protection device can be synchronized based on stimulation-pulse sensing, trigger pulses from a cardiac stimulator, R-wave sensing, or high-voltage sensing. FIG. 12 is a schematic diagram of an electroporation system disposed in a heart (1002) of a patient (1000) that includes an ablation device (1010), signal generator (1022), cardiac stimulator (1028), pacing device (1030), and protection device (1050). The signal generator (1022) may be coupled to the ablation device (1010). The signal generator (1022) may be configured to generate pulse waveforms delivered to electrodes (1012) of the ablation device (1010) for generating a pulsed electric field for ablation. The pacing device (1030) may be configured to pace the heart (1002) using pacing electrodes (1032, 1034) and/or measure cardiac activity of the heart (1002) (e.g., electrocardiogram) using one or more electrodes (e.g., electrodes (1032, 1034) or other electrodes (not depicted)). The protection device (1050) may be coupled between the cardiac stimulator (1028) and the pacing device (1030). The protection device (1050) can include components that are structurally and/or functionally similar to any of the other protection devices described herein (e.g., protection devices depicted in FIGS. 3A, 3B, 4, 5, 8, 10A-10E, 11, 14-16, 18, and 19).

In some embodiments, the protection device (1050) may be configured to synchronize electrical isolation of the cardiac stimulator (1028) with pulse waveform delivery by the ablation device (1010) based on one or more signals. The protection device (1050) may be synchronized based on the same signal or combination of signals as the signal generator (1022) or independently based on one or more of a stimulation signal (1060) from the cardiac stimulator (1028) (which can also be sent to the signal generator (1022)), measured data (e.g., stimulation-pulse detection signal (1070), R-wave detection signal (1090), and high-voltage detection signal (1092)), and a signal generator signal (1080). In alternative embodiments, the protection device (1050) and the signal generator (1022) can be activated based on different signals or a different combination of signals. For instance, the protection device (1050) may be controlled based on a cardiac pacing signal (1060) and pulse waveform delivery may be based on a detected R-wave signal (1090). In embodiments using stimulation pulse sensing, the sensing can be implemented with a predetermined threshold (e.g., about 5V) in order to reduce false-positives that may increase the number of disconnections between the cardiac stimulator (1028) and/or other protected electronic components and the patient (1000). To provide another layer of safety, a protection device for any external electronic components can be configured to provide a low-impedance connection between the protected electronic components and the patient when unpowered. FIG. 14 is a block diagram of electrical component(s) (1210) (e.g., including sensitive equipment or circuitry) coupled to a patient (1220) via a protection device (1200). One or more electrical component(s) (1210) (e.g., monitoring equipment, cardiac stimulator, such as any described herein) may be coupled to the patient (1220) and may be susceptible to induced current from high voltage ablation energy delivery. Each of the electrical component(s) (1210) may be coupled to the protection device (1200) to selectively electrically isolate those components from devices disposed in the heart of the patient (1220). The protection device (1200) can include components that are structurally and/or functionally similar to any of the other protection devices described herein (e.g., protection devices depicted in FIGS. 3A, 3B, 4, 5, 8, 10A-10E, 11, 12, 15, 16, 18, and 19).

The protection device (1200) can be configured such that the electrical component(s) (1210) are electrically coupled (e.g., through a low-impedance connection) to the patient (1220) when the protection device (1200) is unpowered. This safety feature may allow for patient connection by default and allow the electrical component(s) (1210) to operate even if power is lost to the protection device (1200). For example, a cardiac stimulator (e.g., cardiac stimulator (28)) included in the electrical component(s) (1210) may provide pacing to the patient (1220) when the protection device (1200) is powered off.

A first signal (1202) (e.g., control signal) may be configured to control the protection device (1200) and provide electrical isolation through a first switch (1206) as described herein. A second signal (1204) (e.g., a power signal) may be configured to control the protection device (1200) through a second switch (1208). In some embodiments, the second switch (1208) may comprise a relay (e.g., reed switch, or solid-state type switch) configured in parallel to the first switch (1206) used for isolation/blanking and configured to switch open when the protection device (1200) is powered. In some embodiments, the first switch (1206) can include an electro-mechanical relay (e.g., reed relay), a solid-state relay, and/or a MOSFET device. For example, the first switch (1206) can include two back-to-back MOSFETs with common source terminals, as depicted in FIG. 5. The second pathway provided via the second switch (1208) can normally be set to a closed state to provide the low-impedance connection between the electrical component(s) (1210) and the patient (1220).

FIG. 15 provides another example embodiment for a system including a protection device (1300). Specifically, FIG. 15 is a block diagram of electrical component(s) (1310) coupled to a patient (1320) via a protection device (1300). One or more electrical component(s) (1310) (e.g., monitoring equipment, cardiac stimulator) may be coupled to the patient (1320) via the protection device (1300) configured to selectively electrically isolate those electrical components) (1310) from devices disposed in the heart of the patient (1320), e.g., via a first signal (1302). The protection device (1300) can include components that are structurally and/or functionally similar to any of the other protection devices described herein (e.g., protection devices depicted in FIGS. 3A, 3B, 4, 5, 8, 10A-10E, 11, 12, 14, 16, 18, and 19). In a similar manner as described with respect to FIG. 14, the electrical component(s) (1310) may be electrically coupled to the patient (1320) when the protection device (1300) is unpowered via normally closed switches that are disposed in parallel to the blanking/protection components. When power is provided to the protection device (1300), a signal (1304) corresponding to the power can open the normally closed switches. In some embodiments, the protection device (1300) may include additional circuit protection and filtering functionality configured to reduce peak-to-peak voltages of high slew rate and/or high voltage signals, even when the protection device (1300) is un-powered and/or when the electrical component(s) (1310) are not isolated from the patient (1320). The protection device (1300) may include one or more of a passive filter device (1330) (as described above with reference to FIG. 2), common mode protection device (1340), and differential/high voltage protection device (1350), which may include one or more common and differential mode chokes using ferrites/magnetics, inductor and capacitor-based filters, and differential high voltage and differential clamping components including one or more of transient-voltage-suppression (TVS) diodes/tranzorbs, gas discharge tubes, and thyristors. In some embodiments, the methods, systems, and devices disclosed herein may comprise one or more of the methods, systems, and devices described in U.S. application Ser. No. 62/667,887, filed on May 7, 2018, and titled “SYSTEMS, APPARATUSES, AND METHODS FOR FILTERING HIGH VOLTAGE NOISE INDUCED BY PULSED ELECTRIC FIELD ABLATION,” incorporated above in its entirety.

In some cardiac stimulators (e.g., electrophysiology laboratory stimulator systems), patient connections may be monitored for high impedance to alert a user of disconnections. To prevent undesirable warnings during use of a protection device (e.g., during blanking intervals), a fixed known impedance (e.g., by way of a fixed resistor having a value in a range expected by the stimulator such as, for example, 1 kOhm) can be provided to the connections to the stimulator. FIG. 16 is a block diagram of electrical component(s) (1410) coupled to a patient (1420). One or more electrical component(s) (1410) (e.g., monitoring equipment, cardiac stimulator) may be coupled to the patient (1420) via a protection device (1400) configured to selectively electrically isolate such components from devices disposed in the heart of the patient (1420) via a signal (1402). The protection device (1400) can include components that are structurally and/or functionally similar to any of the other protection devices described herein (e.g., protection devices depicted in FIGS. 3A, 3B, 4, 5, 8, 10A-10E, 11, 12, 14, 15, 18, and 19).

A cardiac stimulator included in the electrical component(s) (1410) may continuously monitor the electrical connection to the patient (1420) and generate a disconnection signal (e.g., alarm signal to the user) when disconnection (e.g., high-impedance) is detected. In some embodiments, in order to inhibit generation of a disconnection signal by the system (1410) during a protection interval of the protection device (1400), the protection device (1400) may provide the cardiac stimulator with a predetermined impedance (1440) (e.g., between about 100 Ohm and about 10 kOhms) in a range that the stimulator would expect to correspond to normal operations. For example, the protection device (1400) operating during the protection interval may send a signal to close a switch in series with a resistor (1440) that can then provide the fixed impedance value. The quick transition between “patient connection” and “open-circuit with fixed resistor load” can be sufficiently fast to prevent any warnings or alerts by the cardiac stimulator. In some embodiments it may be useful to switch-in the load to the electrical component first, a short time interval before disconnecting the patient connections (e.g., on the order of 1 us to 100 us). If this is done, there is not a small amount of time when the electrical component sees an open-circuit. The patient-connections can then be connected before (e.g., immediately before) the resistive load is disconnected. Another implementation optimization is to provide the “load resistor” on both sides (patient side as well) so that there is symmetry in the implementation and the protection device may be plugged in either way.

In some instances, with a protection device as implemented in FIG. 16, there may be introduction of switching artifacts and short voltage spikes on the patient. FIGS. 17A and 17B are schematic illustrations of a time sequence of cardiac stimulation (1510), electrocardiogram (1520), pulsed field ablation delivery (1530), and protection interval (1540) channels, where a switching artifact (1526) may occur when a protection interval ends. FIG. 17A illustrates a single cardiac cycle and FIG. 17B illustrates a plurality of cardiac cycles, as described in more detail herein. The stimulation or pacing signal (1510) may be periodic and may comprise a rectangular pulse having a width of between about 0.1 ms and about 100 ms. In some embodiments, the pacing pulses (1512) may be delivered using any of the pacing devices (e.g., pacing devices (230, 630, 1030)) described herein. The pacing pulses (1512) may correspond to one or more of ventricular and atrial cardiac pacing. In response to the pacing pulses (1512), the cardiac cycle of the heart may synchronize with the pacing pulses (1512). For example, the QRS waveform (1522) in FIGS. 17A and 17B is synchronized with the pacing pulse (1512).

In some embodiments, a pulse waveform (1532) and protection interval (1542) may synchronize with one or more of the pacing signal (1512) and the cardiac cycle (e.g., via R-wave detection), as described in embodiments above. For example, a pulse waveform (1532) may have a first length and a protection interval (1542) may have a second length at least as long as the first length. The pulse waveform (1532) may be delivered after a first delay (1534) from a trailing edge (1514) of the cardiac pacing pulse (1512). The first delay (1534) may be a predetermined value. For example, the first delay (1534) may be between about 1 ms and about 20 ms. Likewise, a protection interval (1542) may synchronize with the cardiac pacing pulse (1512) after a second delay (1544). In this manner, a cardiac pacing signal (1512) may be configured to trigger the pulse waveform (1532) and the protection interval (1542).

In embodiments including a protection device as implemented in FIG. 16, switching artifact (1526) (e.g., voltage spike) may be introduced in the patient and picked up in the electrocardiogram (1520) (e.g., via an electrocardiogram recording system) that may interfere with analysis of cardiac activity. For example, a protection artifact (1526) may coincide with a trailing edge (1528) of a protection interval (1542). FIG. 17B illustrates an embodiment where a protection interval (1542) is provided for each heartbeat and may, for example, generate an artifact (1526) for each protection interval/heartbeat. In some embodiments where less coordinated control of a protection device is available, one or more protection intervals (1542) may be provided without a corresponding pulse waveform (1532). This may occur, for example, in embodiments where the pulse waveform (1530) and protection signal (1540) are independently synchronized using different signals.

When artifacts (1526) are sufficiently large in magnitude, they can cause clinical misinterpretation of cardiac activity. To mitigate this risk, several options are available. First, the protection module can be integrated with a signal generator such that the protection interval (1542) is provided only when there is a corresponding pulse waveform (1532) and not when a pulse waveform (1532) is not delivered. Accordingly, a protection interval (1542) is provided when necessary to electrically isolate a cardiac stimulator or other protected electrical components (e.g., monitoring equipment) from a high voltage pulse waveform. With this implementation, no unnecessary protection-switching occurs, and for artifacts (1526) generated with a pulse waveform, the high voltage ablation energy delivered to heart tissue saturates the heartbeats such that the artifacts (1526) do not present an issue.

Second, for independent protection devices where less coordinated control with pulsed field ablation device is possible, switching artifacts (1526) can be reduced, e.g., using placement of low-value capacitors across the isolation switches or between the protected channels to absorb some of the high-frequency local switching energy in the protection device. The implementation of previously described passive filtering components, e.g., see FIG. 2, can also be implemented to reduce artifacts (1526). Other options include using additional switches/MOSFETs to temporarily short pairs of signals together (e.g., stimulator +/− and patient +/−) before re-connecting to the patient, temporarily switching in a resistive load on the patient-side during a blanking interval, etc.

FIG. 18 is a block diagram of electrical component(s) (1610) coupled to a patient (1620) via a protection device (1600) including one or more capacitors for reducing artifacts. One or more electrical component(s) (1610) (e.g., monitoring equipment, cardiac stimulator) may be coupled to the patient (1620) via a protection device (1600) configured to selectively electrically isolate such components from devices disposed in the heart of the patient (1620). In some embodiments, the protection device (1600) may be configured to reduce a magnitude of an artifact (e.g., artifact (1526)). The protection device (1600) can include components that are structurally and/or functionally similar to any of the other protection devices described herein (e.g., protection devices depicted in FIGS. 3A, 3B, 4, 5, 8, 10A-10E, 11, 12, 14-16, and 19).

The protection device (1600) may include one or more series protection switches (1602) and resistors (1606). The protection device (1600) may further include one or more of capacitors (1604) configured parallel to corresponding switches (1602) and resistors (1606). The capacitors (1604) may be configured to receive a portion of any voltage spike generated by the switching operations of protection device (1600). Additionally or alternatively, the protection device (1600) may include one or more circuit components described in FIG. 15 (e.g., filter device (1330), common mode protection device (1340), differential/high voltage protection device (1350)) configured to reduce switching artifacts.

The resistors (1606) can be arranged in series with switches that can be configured to close prior to closing the series protection switches (1602) to reduce artifacts produced by the switching of the protection switches (1602). For example, the switches in series with the resistors (1606) may be configured to close prior to the series protection switches (1602) closing in order to provide a temporary pathways for one or more of the electrical component(s) (1610) and the patient (1620), thereby reducing risk of artifacts from the series protection switches (1602) when the loads are subsequently disconnected.

FIG. 19 is a schematic diagram of a system for ablation via irreversible electroporation including a protection device (1900). The system may include a signal generator (1930), ablation device (1932), and electronic component(s) (1940). In some embodiments, the electronic component(s) (1940) may be implemented as a signal detector, e.g., such as monitoring equipment for monitoring physiological data of a patient (1920). The protection device (1900) can include component(s) that are structurally and/or functionally similar to other protection devices described herein (e.g., protection devices depicted in FIGS. 3A, 3B, 4, 5, 8, 10A-10E, 11, 12, 14-16, 18, and 19).

The signal generator (1930) may be configured to generate pulse waveforms delivered to tissue by electrodes (not shown) of the ablation device (1932). In some embodiments, the signal generator (1930) may be configured to generate high voltage ablation pulse waveforms for irreversible electroporation of tissue, such as, for example, pulmonary vein ostia. In some embodiments, the protection device (1900) may be electrically coupled to the patient (1920) via a set of patient connections (1924). For example, one or more electrode(s) and/or sensor(s) may be placed externally on and/or internally within the patient (1920), e.g., to measure physiological data of the patient (1920). The protection device (1900) may be coupled between the patient (1920) and the electronic component(s) (1940).

In some embodiments, the signal generator (1922) may be configured to generate the pulse waveform in synchronization with the indication of a pacing signal and/or within a common refractory window. For example, in some embodiments, the common refractory window may start substantially immediately following a pacing signal (or after a very small delay) and last for a duration of approximately 250 milliseconds (ms) or less thereafter. In such embodiments, an entire pulse waveform may be delivered within this duration.

In some embodiments, the electronic components (1940), the protection device (1900), and/or the signal generator (1930) may be in communication with one another, e.g., for coordinating timing of the pulse waveform delivery and/or protection device control signal delivery. For example, the signal generator (1930) can be operatively coupled to the protection device (1900) such that the signal generator (1930) can deliver signals (e.g., a synchronization signal (1912)) to the protection device (1900), e.g., for synchronizing operation of one or more component(s) of the protection device (1900) with the delivery of the ablation pulse waveform. In an embodiment, the signal generator (1930) can deliver a synchronization signal (1912) to the protection device (1900) on a periodic basis that indicates to the protection device (1900) of a delivery timing of the pulse waveform. As depicted in FIG. 19, the signal generator (1930) and the protection device (1900) can be separate devices. Alternatively, in some embodiments, the protection device (1900) may be integrated with the signal generator (1930) in a single console.

The protection device (1900) may be configured to form an open circuit between the electronic component(s) (1940) and one or more patient connections (1924), e.g., sensor(s) or electrode(s) deposed near the site of ablation, at least during delivery of ablation energy by the ablation device (1932). The patient connections (1924) can allow the electronic component(s) 1940 to monitor physiological data of the patient (1920). As described herein, delivery of pulse waveforms to the patient (1920) can induce high voltages and/or currents in patient connections (1924). Accordingly, by isolating these connections (1924) from the electronic component(s) (1940), the protection device (1900) can reduce or prevent transfer of such induced voltages and/or currents to the electronic component(s) (1940), thereby reducing noise interference from entering such components and/or damaging such components. When a pulse waveform is not being delivered to the patient (1920), the protection device (1900) may be configured to electrically couple the electronic components (1940) with the patient connections (1924), e.g., to allow the electronic components (1940) to continue to monitor physiological data of the patient (1920).

The protection device (1900) may comprise a set of one or more switches (e.g., series components) (1902) configured to form an open circuit between the patient connections (1924) and the electronic component(s) (1940). The set of switches (1902) can include one or more of electro-mechanical relays (e.g., reed relays), solid-state relays, and/or MOSFET devices.

In some embodiments, components can be introduced which can electrically connect the protected patient signals to a common node (1906). The protection device (1900), for example, can include channels that extend from each input into an electronic component (1940) and connect them to a common node (1906). Each channel can include a switch (1903) and a resistance element (1904) (e.g., a resistor). When the switches (1903) are closed, the channels can connect the inputs to the electronic components (1940) to the common node (1906). The resistance elements (1904) may be coupled between the inputs and the common node (1906). The resistance elements (1904) can be configured to reduce or minimize resistance when connecting the inputs to the common node (1906). During pulsed field ablation (e.g., delivery of a pulse waveform), to reduce noise present at the input(s) of the electronic component(s) (1940) (e.g., monitoring equipment), the inputs can be shorted together to reduce the amplitude of any differential noise. The switches (1902) may be open, e.g., to isolate the electronic component(s) (1940) from the patient connection(s) (1924), but any residual noise that is transferred or picked up through the open-circuit series components (e.g., switches (1902)) during the pulsed field ablation delivery can be tied to the common node (1908) and the signal amplitude detected at the electronic component(s) (1940) (e.g., measured by the monitoring equipment) can be reduced or rendered small.

In some embodiments, components can be introduced that can connect the common node (1906) to a ground (1909) (e.g., the chassis or earth ground), e.g., to further reduce noise that can be picked up at the input(s) to the electronic component(s) (1940) during pulsed field ablation delivery. By coupling inputs that are electrically tied together (e.g., via the common node (1906)) to a ground connection, the protection device (1900) can reduce the amplitude of common mode noise and prevent large DC voltages above earth ground from being transferred into the electronic component(s) (1940) (e.g., an input amplifier of a monitoring device). Coupling the common node (1906) to ground (1909) can also reduce the chances for interference from the pulsed field ablation delivery affecting the electronic component(s) (1940).

In some embodiments, components can be introduced which can filter high-frequency signals on ground connections (e.g., earth-ground connections) at the signal generator (1930) and/or the protection device (1900) (or other protection circuitry). For example, the signal generator (1930) may be coupled to ground via an inductance filter (e.g., a ferrite clamp, ferrite toroid, or series inductor) (1914). Additionally or alternatively, the protection device (1900) may be coupled to ground via inductance filter (e.g., ferrite) (1901). The noise created upon ablation delivery by the signal generator (1930) can be conducted through the patient to the patient connection (1902), but it can also be emitted on the ground connection of the signal generator (1930). To reduce the noise caused by the connection of the signal generator (1930) to ground, components such as ferrite clamps, ferrite toroids, or series inductors (e.g., filter (1914)) may be used to filter the high-frequency noise on these connections and to reduce the amplitude measured at the ground connection of the electronic component(s) 1940.

FIGS. 20A-20C are schematic illustrations of time sequences of establishing connections among one or more of inputs or signals to the electronic components (1940), the common node (1906), and ground (1909), during pulsed field ablation delivery. Time sequences (2012, 2014, 2016) represent timing of connecting the inputs to the electronic components (1940) to the common node (1906), time sequences (2022, 2024, 2026) represent timing of connecting the common node (1906) to the ground (1909), time sequences (2032, 2034, 2036) represent timing of forming the open circuit between the patient connections (1924) and the electronic component(s) (1940) using the series components or switches (1902), and time sequences (2042, 2044, 2046) represent the timing of the pulse waveform delivery (e.g., via the signal generator (1930)).

FIG. 20A illustrates a time sequence (2010) for operating the components of the protection device (1900) that ties the inputs to the electronic components (1940) together via the common node (1906) and simultaneously ties the common node (1906) to ground (1909), as shown by (2012, 2022). As depicted, the time sequence (2010) allows the electronic component(s) (1940) to continue to see a low-impedance load between its inputs (e.g., from patient connections (1924)) throughout the ablation delivery procedure and ensures that the common mode DC level is low. The time sequence (2010) ensures that the inputs (e.g., from patient connections (1924)) to the electronic components are not high-impedance, which may undesirably allow large noise pick-up. After the inputs to the electronic components (1940) are tied together and to ground (1909), the series components can form an open circuit (e.g., switches (1902) can be set to an open state) between the patient connections (1924) and the electronic components (1940), which isolates the electronic components (1940) from the patient (1920), as shown by (2032). After the open circuit is established, the pulse waveform can be delivered to ablate tissue, as shown by (2042). After the ablation procedure is complete and the pulse waveform is no longer being delivered to the patient (1920), the series components can re-connect the patient (1920) to the electronic equipment (1940). Then following that, the inputs to the electronic components (1940) can be released from their common node and earth-ground connections (e.g., the switches (1903) can be set to an open state), and the electronic components (1940) can again be configured to receive data (e.g., physiological data) from the patient connections (1924), free of any pulsed field ablation interference.

FIG. 20B depicts another time sequence (2020) for operating the components of the protection device (1900). The time sequence (2020) of FIG. 20B is similar to the time sequence (2010) of FIG. 20A, except that the connection of the common node (1906) to ground (1909) does not occur simultaneously with the connection of the inputs of the electronic components (1940) to the common node (1906). In some embodiments, the connection of the common node (1906) to ground (1909) (e.g., switch (1908) switching to a closed state) may occur when the series components of the protection device (1900) transitions to the open circuit configuration (e.g., switches (1902) transition to the open state), as shown by (2024, 2034). This can ensure that the patient (1920) is not temporarily earth-grounded (i.e., the patient connections (1924) are not coupled to earth ground (1909)) after the inputs to the electronic component(s) 1940 are connected to the common node (1906) but the series components have yet to transition into an open state. By not having the patient (1920) temporarily earth-grounded, any residual current within the system does not have a pathway through the patient (1920) to ground. Then once the patient signals are open circuit (e.g., switches (1902) transition to the open state), energy (e.g., ablation pulse waveform) may be delivered to the patient (1920) and, upon completion of the energy delivery, the patient signals can be re-connected (e.g., switches (1902) transition back to the closed state), simultaneous with the release of the earth-ground connection (e.g., switch (1908) switches back to an open state). Following these events, the inputs to the electronic component(s) (1940) can be released from the common node (1906) to allow the electronic component(s) 1940 to measure patient signals again via the patient connections (1924), without interference or noise from the ablation energy delivery.

FIG. 20C depicts another time sequence (2030) for operating the components of the protection device (1900). The time sequence (2030) of FIG. 20C is similar to the time sequences (2010, 2020) of FIGS. 20A and 20B, except that a connection is not formed between the common node and the ground at any point during the sequence, such that the common node (1906) is left floating. This may ensure that an earth ground (1909) input connection does not interfere with the inputs of the electronic component(s) (1940). As described above, during an ablation procedure, high-frequency signals can travel from the signal generator (1030) and/or other components of the system to earth ground (1909). As such, establishing a connection with the ground (1909) can cause such signals to interfere with the operation of the electronic components (1940), e.g., by generating noise. While the inductance filters (1901, 1914) described above can be used to reduce some of these high-frequency signals, such inductance filters (1901, 1914) may need to be adjusted, based on whether various components of the system are in an open or closed state, and therefore may be imperfect at filtering the high-frequency signals. Similar to the time sequences (2010, 2020), the series components can be switched to an open circuit state and ablation energy can be delivered while the series components are in the open circuit state. Following delivery of the ablation energy, the series components can switch back to the closed circuit state, re-connecting the patient connections (1924) to the electronic components (1940), and the inputs to the electronic component(s) 1940 can be released from the common node (1906) connection.

Methods

Also described here are methods for protecting electronic circuitry from induced currents and voltages during a tissue ablation process performed in one or more heart chamber(s) using the systems and devices described herein. In an embodiment, the heart chamber(s) may be the left atrial chamber and include its associated pulmonary veins. Generally, the methods described here include introducing and disposing a pacing device (e.g., pacing device (230)) in contact with one or more heart chamber(s). The pacing device may deliver a pacing signal to the heart using a cardiac stimulator (e.g., cardiac stimulator (28, 28′)) and/or measure cardiac activity. An ablation device (e.g., ablation device (210)) may be introduced and disposed in contact with one or more pulmonary vein ostial or antral regions. A pulse waveform may be delivered by one or more electrodes (e.g., electrodes (212)) of the ablation device to ablate tissue. In some embodiments, a protection device (e.g., protection device (250)) can be in an open-circuit configuration to isolate one or more sensitive electrical components (e.g., cardiac stimulator, monitoring equipment) during the delivery of the pulse waveform. Such electrical components may otherwise be electrically coupled to the pacing device and configured to deliver pacing signals to the heart and/or receive cardiac activity measurements. In some embodiments, a control signal may be generated to control the open-circuit interval (e.g., protection interval) of the protection device. The control signal may be based on one or more of a cardiac pacing signal, pulse waveform signal (e.g., signal generator signal), measured cardiac activity (e.g., R-wave detection), combinations thereof, and the like.

Additionally or alternatively, the pulse waveforms may include a plurality of levels of a hierarchy to reduce total energy delivery, e.g., as described in International Application Serial No. PCT/US2019/031135, filed on May 7, 2019, and titled “SYSTEMS, APPARATUSES AND METHODS FOR DELIVERY OF ABLATIVE ENERGY TO TISSUE,” and incorporated herein by reference.

In some embodiments, the ablation devices (e.g., ablation device (210)) described herein may be used for epicardial and/or endocardial ablation. Examples of suitable ablation catheters are described in International Application Serial No. PCT/US2019/014226, incorporated by reference above.

FIG. 6A is an example method (400) of tissue ablation where ablation energy is delivered in synchrony with cardiac pacing. In some embodiments, the voltage pulse waveforms described herein may be applied during a refractory period of the cardiac cycle so as to avoid disruption of the sinus rhythm of the heart. The method (400) includes introduction of a pacing device (e.g., pacing device (230)) into an endocardial space, e.g., of a right ventricle, at (402). The pacing device may be advanced to be disposed in contact with the cardiac tissue, at (404). For example, sensor electrodes may be configured for cardiac activity measurement (e.g., ECG signals) and pacing electrodes may be configured for delivering pacing signals and may be disposed in contact with an inner endocardial surface, for example in the right ventricle. An ablation device (e.g., ablation device (210)) may be introduced into an endocardial space, e.g., of a left atrium, at (406). The ablation device may be advanced to be disposed in contact with a pulmonary vein ostium, at (408). In some embodiments, a pacing signal may be generated by a cardiac stimulator (e.g., cardiac stimulator (28, 28′)) for cardiac stimulation of the heart, at (410). The pacing signal may then be applied to the heart, at (412), using the pacing electrodes of the pacing device. For example, the heart may be electrically paced with the pacing signal to ensure pacing capture to establish periodicity and predictability of the cardiac cycle. One or more of atrial and ventricular pacing may be applied. Examples of applied pacing signals relative to patient cardiac activity are described in more detail herein, e.g. FIG. 7B.

In some embodiments, pacing capture may be automatically confirmed by one or more of a signal generator (e.g., signal generator (222)), the cardiac stimulator, or other processor operatively coupled to one or more components of the system. In some embodiments, pacing capture can be confirmed by a user. For example, the user may confirm pacing capture using a user interface (e.g., an input/output device such as a touch screen monitor or other type of monitor) based on measured cardiac activity signals. If the signal generator, processor, and/or the user viewing the displayed cardiac output, determines that there is an absence of pacing capture, pulse waveform generation may be prohibited and the user may be prompted to adjust system parameters by, for example, repositioning the pacing device to improve tissue engagement and/or modify pacing signal parameters (e.g., pulse width, pulse amplitude, pulse frequency, etc.).

In some embodiments, the pacing device may measure cardiac activity (e.g., ECG signals) corresponding to electrical cardiac activity of the heart, at (414). For example, the measured cardiac activity may include a measured cardiac pacing pulse, R-wave, etc.

A control signal or protection signal may be generated based on one or more of a cardiac pacing signal, pulse waveform signal (e.g., a signal received form a signal generator), measured cardiac activity (e.g., R-wave detection, predetermined voltage thresholds), combinations thereof, and the like, and applied to the protection device at (418). For example, the protection signal may be generated based on a cardiac pacing signal received from a cardiac stimulator (e.g., cardiac stimulator (28)) or a ECG signal measured by the pacing device (e.g., pacing device (230)). As another example, the protection signal may be generated based at least in part on a pulse waveform signal received from a signal generator (e.g., signal generator (222)). The protection signal may have a predetermined time period and length. The cardiac stimulator and/or other electronic components may be electrically isolated throughout a protection interval in response to the protection signal, at (418). For example, a protection device coupled to a pacing device may electrically isolate the cardiac stimulator from high voltage pulsed electric field ablation signals delivered by an ablation system (e.g., signal generator (222), ablation device (210), etc.) based on a received protection signal.

In some embodiments, a protection signal may synchronize electrical isolation of a cardiac stimulator with delivery of ablation energy to tissue. For example, the protection signal may be generated based on one or more of a cardiac pacing signal, measured cardiac activity, and signal generator signal, as described in detail herein. Additionally or alternatively, a protection device may generate a protection signal even when a cardiac stimulator is not actively delivering pacing signals during a pulsed electric field ablation procedure. This may be useful, for example, in case of a medical emergency requiring rapid cardiac pacing. Such protection can also be useful to isolate electronic components (e.g., medical electronic equipment other than the ablation device including, without limitation, ECG recording or monitoring equipment, electroanatomical mapping systems, device navigation/tracking systems, etc.) that are often present in a clinical procedure room. It is important to note that subsequent to delivery of a set of ablation pulses, the protection device is deactivated (424) so that connections are restored between the medical device electrode(s) and the respective electronic component(s) (e.g., medical electronic equipment, cardiac stimulator, electroanatomical mapping system, ECG recording or monitoring system, device navigation/tracking system, etc.).

The signal generator (e.g., signal generator (222) or any processor associated therewith may be configured to generate a pulse waveform in synchronization with the protection interval, at (420), e.g., based on predetermined criteria. For example, the pulse waveform may be generated during a refractory time period, which starts after and ends before the protection interval. The refractory time period may follow a pacing signal. For example, a common refractory time period may be between both atrial and ventricular refractory time windows. A voltage pulse waveform may be applied in the common refractory time period. In some embodiments, the pulse waveform and/or protection signal may be generated with a time offset with respect to the indication of the pacing signal. For example, the start of a refractory time period may be offset from the pacing signal by a time offset. The voltage pulse waveform(s) may be applied over a series of heartbeats over corresponding common refractory time periods. In some embodiments, the pulse waveform and protection signal may be generated based on the same or different signal or information (e.g., pacing signal, sensed R-wave).

The ablation device, in response to receiving the pulse waveform, can generate an electric field (e.g., pulsed electric field) that is delivered to tissue, at (422).

In some embodiments, hierarchical voltage pulse waveforms having a nested structure and a hierarchy of time intervals as described herein may be useful for irreversible electroporation, providing control and selectivity in different tissue types. For example, a pulse waveform may be generated by a signal generator (e.g., the signal generator (222)) and may include a plurality of levels in a hierarchy. A variety of hierarchical waveforms may be generated with a signal generator as disclosed herein. For example, the pulse waveform may include a first level of a hierarchy of the pulse waveform including a first set of pulses. Each pulse has a pulse time duration and a first time interval separating successive pulses. A second level of the hierarchy of the pulse waveform may include a plurality of first sets of pulses as a second set of pulses. A second time interval may separate successive first sets of pulses. The second time interval may be at least three times the duration of the first time interval. A third level of the hierarchy of the pulse waveform may include a plurality of second sets of pulses as a third set of pulses. A third time interval may separate successive second sets of pulses. The third time interval may be at least thirty times the duration of the second level time interval.

In some embodiments, the pulse waveform may be delivered to pulmonary vein ostium of a patient via a set of splines of an ablation device (e.g., ablation device (210)), or to a device positioned at any location in the cardiac anatomy or more generally in other parts of the patient anatomy. In some embodiments, voltage pulse waveforms as described herein may be selectively delivered to electrode subsets such as anode-cathode subsets for ablation and isolation of the pulmonary vein. For example, a first electrode of a group of electrodes may be configured as an anode and a second electrode of the group of electrodes may be configured as a cathode. These steps may be repeated for a desired number of pulmonary vein ostial or antral regions to have been ablated (e.g., 1, 2, 3, or 4 ostia). Suitable examples of ablation devices and methods are described in International Application No. PCT/US2019/014226, incorporated above by reference.

FIG. 6B is an example method (1900) of tissue ablation where ablation energy is delivered asynchronously (with no cardiac pacing). The ablation device is introduced in the patient anatomy and positioned in a region of interest, for example at a location in the cardiac anatomy where it is desired to ablate, at (1905). The protection device may be activated at (1909), e.g., by a suitable control signal that may be coupled directly to hardware switched isolation circuitry or to a processor that controls switched isolation circuitry. As used herein, a control element may refer to one or more of a control signal, processor, and a switch circuit (e.g., switched isolation circuitry). Thus, the electronic components or equipment to be protected are isolated from possible pickup of ablation pulses over an isolation time interval. A pulse waveform is generated at (1913) and delivered to tissue at (1917) within the isolation time interval. Subsequent to delivery of the ablation pulses at (1917), the protection device is deactivated at (1920) so as to restore electrical connectivity between the electronic component(s) or equipment and any relevant patient-contact electrodes. Such protected electronic equipment can include one or more cardiac stimulators, electroanatomical mapping systems, ECG recording/monitoring systems, device navigation/tracking systems, etc.

For example, in embodiments where a cardiac stimulator is used to pace a heart over portions of a pulsed electric field ablation procedure, a patient connection between the cardiac stimulator and the heart needs to remain intact for the duration of a pacing or stimulation pulse. In such embodiments, a protection signal (e.g., control signal for activating a protection device) can synchronize electrical isolation of a cardiac stimulator with delivery of ablation energy to tissue. FIG. 7A is a schematic illustration of a time sequence of cardiac stimulation (510), pulsed electric field ablation delivery (530), and protection interval (540) (e.g., blanking or open-circuit) channels. FIG. 7B is a schematic illustration of a time sequence of cardiac stimulation (510), electrocardiogram (520), pulsed electric field ablation delivery (530), and protection interval (540) channels. The cardiac stimulation (510) may comprise a set of periodic pacing pulses (512). Each pacing pulse (512) may comprise a rectangular pulse having a width of between about 0.1 ms and about 20 ms. The pacing pulses (512) may be generated by a stimulator (e.g., stimulator (28, 28′)) and delivered to cardiac tissue using a pacing device (e.g., pacing device (230)). The pacing pulses (512) may correspond to one or more of ventricular and atrial cardiac pacing. In response to the pacing pulses (512), the cardiac cycle of the heart may synchronize with the pacing pulses (512). For example, the QRS waveform (522) in FIG. 7B is synchronized with a respective pacing pulse (512). The T-wave (524) that follows the QRS waveform (522) corresponds to the start of repolarization occurring in the cardiac myocytes. In some embodiments, electrocardiogram (520) may be measured using a pacing device.

In some embodiments, high-voltage application of a pulsed electric field ablation procedure can be synchronized with the cardiac cycle, as depicted in FIGS. 7A and 7B. Pacing can be synchronized to the high-voltage application in several ways. For example, atrial pacing, ventricular pacing, or multi-chamber pacing can be performed. It can be desirable to implement ventricular pacing as the ventricle is more prone to cause arrhythmias (e.g., ventricular tachycardia, ventricular fibrillation) if stimulated during its re-polarization (e.g., T-wave) period. When a stimulation pulse is applied, the high-voltage output of the pulsed electric field ablation can occur concurrent with the pacing or being a predetermined delay after the stimulation pulse.

In some embodiments, delivery of a pulse waveform (532) may begin a first delay (534) (e.g., time interval or period) after the trailing edge (514) of each pacing pulse (512). Each pulse waveform (532) can be applied during an interval (532). In some embodiments, the first delay (534) may be a predetermined value (e.g., input by a user). For example, the first delay (534) may be between about 1 ms and about 100 ms. A second pulse delay (536) can separate the end of the pulse waveform (532) delivery and the start of the T-wave. As described above, it can be desirable to deliver a pulse waveform during a refractory period associated with a cardiac cycle. Accordingly, this second pulse delay (536) represents a safety margin between the pulse waveform (532) and the T-wave (524).

A blanking interval or protection interval (542) can be configured to start immediately or shortly after each pacing pulse (512). The protection interval (542) can be configured to encapsulate the duration during which the pulse waveform (532) is delivered. For example, the protection interval (542) can begin a third delay (544) after the trailing edge (514) of the pacing pulse (512), where the third delay (544) is less than the first delay (534) of the pulse waveform (532). For example, the third delay (544) may be less than about 5 ms. The third delay (544) can be near zero but non-zero such that the protection interval (542) (e.g., open-circuit state, blanking interval) does not overlap the pacing pulse (512) since a closed-circuit connection is necessary for a stimulator and pacing device to deliver the pacing pulse (512). In some embodiments, the protection interval (542) is at least equal to and preferably greater than a first length of the pulse waveform (532) such that the protection interval (542) at least overlaps (e.g., encapsulates) the entire pulse waveform (532). In FIGS. 7A and 7B, the leading and trailing edges (550) of the pulse waveform (532) and protection interval (542) are such that the protection interval (542) is longer than the pulse waveform (532).

If the timing of the high-voltage application of the pulsed electric field ablation is known (e.g., with respect to the pacing or stimulation pulses of the cardiac stimulator), the protection interval (542) can be tailored around the duration of the high-voltage application to ensure that isolation protection encapsulates the high-voltage application interval. The signal generator for the high-voltage application can be configured to have a predetermined amount of delay (e.g., first delay (534)) between the stimulation pulse (e.g., pacing pulse (512)) and the initiation of the high-voltage application to the patient (e.g., leading edge (550) of pulse waveform (532)). This delay can provide sufficient time for the protection element to transition to its isolation state (e.g., open circuit state or configuration) and start the protection interval (542). The protection interval (542) then remains for a duration longer than the high-voltage application interval. The timing of the protection interval (542) and the pulse waveform (532) can be repeated for each cardiac cycle.

In some embodiments, cardiac sensing or monitoring e.g., for an R-wave (e.g., ventricular depolarization/contraction) can be used to synchronize delivery of ablation energy to tissue to the cardiac cycle. For example, the intrinsic R-wave of patient can be sensed and used as a trigger to one or more of ablation energy delivery and electrical isolation. In some embodiments, this R-wave sensing can be used in lieu of pacing the heart. In alternative embodiments, the R-wave sensing can be used along with pacing. For example, pacing can be performed in either the atria or ventricles, and the R-wave response of the captured beat can be sensed and used for synchronization. FIG. 8 is a schematic diagram of an electroporation system disposed in a heart (602) of a patient (600). The electroporation system may include an ablation device (610), signal generator (622) (e.g., pulsed field ablation generator), cardiac stimulator (628), pacing device (630), protection device (650), and one or more signal detectors (670, 672). While two signal detectors (670, 672) are depicted in FIG. 8, it can be appreciated that a single signal detector rather than two independent detectors can be used to accomplish the methods described herein.

The signal generator (622) may be coupled to the ablation device (610) and the signal detector (672). The signal generator (622) may be configured to generate pulse waveforms delivered to electrodes (612) of the ablation device (610), e.g., for delivering ablation energy to the heart (602). The pacing device (630) may be configured to pace the heart using pacing electrodes (632) of pacing device (630). One or more diagnostic devices (636) may be configured to measure cardiac activity of the heart (600) (e.g., electrocardiogram), e.g., using externally placed electrode pads or intra-cardiac electrodes (634). Alternatively, in some embodiments, one or more electrodes of the pacing device (630) and/or ablation device (610) can be used as sensing electrodes, which can connect to a processor (e.g., signal detector (670, 672)) for further detection and/or analysis of components of the cardiac cycle.

The protection device (650) may be coupled between the cardiac stimulator (628) and the pacing device (630). In some embodiments, the protection device (650) may be configured to synchronize electrical isolation of the cardiac stimulator (628) with delivery of ablation energy by the ablation device (610). The one or more signal detectors (670, 672) may be coupled to one or more of the signal generator (622), pacing device (630), protection device (650), and cardiac stimulator (628). As shown in FIG. 8, a first signal detector (670) is coupled to the protection device (650) and a second signal detector (672) is coupled to the signal generator (622). In alternative embodiments, however, a single signal detector can be coupled to both the protection device (650) and the signal generator (622).

Each signal detector (670, 672) may be coupled to a respective diagnostic device (636) coupled to the patient (600). Alternatively, the signal detectors (670, 672) may be integrated with one or more of the signal generator (622), pacing device (630), protection device (650), and cardiac stimulator (628). The signal analyzer (670) may be configured to receive and analyze an electrocardiogram signal to detect one or more R-waves. In some embodiments, R-waves may be detected using an R-wave amplitude threshold, together with some exclusion criteria for noise. When an R-wave is detected, the signal detector (670, 672) can be configured to output a signal to the protection device (650) and signal generator (622). Specifically, the signal detector (672) coupled to the signal generator (622), upon detecting an R-wave, can send a signal to the signal generator (622) to indicate the timing of the R-wave and therefore inform the signal generator (622) as to when to deliver the pulsed electric field ablation. The signal detector (670) coupled to the protection device (650), upon detecting an R-wave, can send a signal to the protection device (650) (e.g., a control signal as described above) to indicate the timing of the R-wave and therefore inform protection device (650) of when to initiate the protection or blanking interval, as further described with reference to FIG. 9.

FIG. 9 is a schematic illustration of a time sequence of cardiac stimulation (710), electrocardiogram (720), pulsed field ablation delivery (730), and protection interval (740) channels. The time sequence depicted in FIG. 9 can include aspects similar to the time sequence depicted in FIG. 7B. The cardiac stimulation (710), e.g., by a cardiac stimulator (628) as depicted in FIG. 8, can provide optional and/or periodic stimulation pulses (712) to a patient (e.g., patient (600)). In an embodiment, the stimulation pulses may be periodic and may comprise a rectangular pulse having a width of between about 1 ms and about 5 ms. In some embodiments, the pacing pulses (712) may be delivered using any of the pacing devices (e.g., pacing device (630)) described herein. The pacing pulses (712) may correspond to one or more of ventricular and atrial cardiac pacing. The electrocardiogram (720) can include one or more P-waves (721), QRS waveforms (722), and T-waves (724). The P-wave (721) corresponds to atrial depolarization. The T-wave (724) that follows the QRS waveform (722) corresponds to the start of repolarization occurring in the cardiac myocytes. In some embodiments, delivery of a pulse waveform (732) may be synchronized with R-wave (726) detection, e.g., immediately upon R-wave detection or after a first delay (734). In embodiments where a protection device (e.g., protection device (650)) is used to isolate certain electronic components from the patient during pulsed electric field ablation delivery, it can be desirable to implement a predetermined delay such that there is sufficient time for the protection device to isolate such electronic components after R-wave detection and before pulsed electric field ablation delivery. In some embodiments, the first delay (734) may be a predetermined value. For example, the first delay (734) may be between about 1 ms and about 5 ms. In some embodiments, the pulse waveform (732) may be separated from a T-wave (724) by a second delay (736), e.g., to provide a safety margin.

In some embodiments, a protection device (e.g., protection device (650)) that implements a protection interval (742) (e.g., open-circuit or blanking interval) can use R-wave (726) detection for synchronization. The protection device can start the protection interval (742) after a third delay (744) from the R-wave (726). The third delay (744) may be less than the first delay (734). The third delay (744) may be less than about 5 ms. When a protection device is used with cardiac stimulation, the protection interval (742) (e.g., open-circuit state, blanking interval) can be configured to not overlap the stimulation or pacing pulse (712). The protection interval (742) may be at least equal to, and preferably greater than, a length of the pulse waveform (732) such that the protection interval (742) at least overlaps (e.g., encapsulates) the entire pulse waveform (732). In some embodiments, the pulse waveform (732) and the protection interval (742) can be implemented independently (e.g., with separate R-wave detectors (670, 672)) or concurrently (e.g., with a single R-wave detector (670)). By starting the protection interval (742) immediately or shortly after R-wave (726) detection and having it continue for longer than the expected pulsed field ablation delivery duration, the protection interval (742) can protect electronic components (e.g., sensitive equipment such as, for example, the cardiac stimulator) even when intra-cardiac pacing is not actively being used during a pulsed field ablation procedure. It can be important to protect such electronic components such as a cardiac stimulator, even if such equipment is not actively being used during an ablation procedure, in the event of medical emergencies that may require rapid pacing or other types of pacing and therefore permitting such electronic components to be functional, connected, and ready to use throughout the procedure.

Protection or isolation coverage of certain electronic components during a high voltage interval can be implemented using a fixed blanking interval sufficiently long in duration to cover a longest expected ablation interval or an adjustable or settable blanking interval (e.g., which a user or system can set to a value based on expected pulsed field ablation time). FIG. 13 is a schematic illustration of a time sequence of a cardiac stimulation (1110), electrocardiogram (1120), pulsed field ablation delivery (1130), and protection interval (1140) channels. The cardiac stimulation (1110) channel can optionally include pacing or stimulation signals (1112) that may be periodic and may comprise a rectangular pulse having a width of between about 0.1 ms and about 100 ms. In some embodiments, the pacing pulses (1112) may be delivered using any of the pacing devices (e.g., pacing devices (230, 630, 1030)) described herein. The pacing pulses (1112) may correspond to one or more of ventricular and atrial cardiac pacing. In response to the pacing pulses (1112), the cardiac cycle of the heart may synchronize with the pacing pulses (1112). For example, the P-wave (1121), QRS waveform (1122), and T-wave (1124) in FIG. 13 can be synchronized with the pacing pulse (1112). The P-wave (1121) corresponds to atrial depolarization, and the T-wave (1124) that follows the QRS waveform (1122) corresponds to the start of repolarization occurring in the cardiac myocytes.

In some embodiments, a pulse waveform (1132) and protection interval (1142) may synchronize based on one or more of pacing or stimulation pulse sensing (1144) and R-wave detection (1124). The pulse waveform (1132) may have a first length or duration (1134), and the protection interval (1142) may have a second length or duration (1148) at least as long as the duration of the pulse waveform (1132). The duration (1148) of the protection interval (1142) can be fixed or adjustable. The pulse waveform (1134) may be delivered after a first delay (1136) from a trailing edge (1114) of the cardiac pacing pulse (1112) (e.g., as signaled by a cardiac stimulator or detected). The first delay (1136) may be a predetermined value. For example, the first delay (1136) may be between about 1 ms and about 5 ms. Likewise, a protection interval (1142) may synchronize with the cardiac pacing pulse (1112) (e.g., as signaled by a cardiac stimulator or detected) after a second delay (1144). In this manner, a cardiac pacing signal (1112) may be configured to trigger the protection interval (1142). The protection interval (1142) (e.g., open-circuit state, blanking interval) can overlap the entire pulse waveform (1132).

In some embodiments, the pulse waveform (1132) and protection interval (1142) may synchronize with R-wave detection (1124), e.g., after respective third delay (1138) and fourth delay (1146). In this manner, the R-wave detection (1124) may be configured to trigger the protection interval (1142). The R-wave detection can be implemented using any of the systems as described herein. The third delay (1138) may be a predetermined value. For example, the third delay (1138) may be between about 1 ms and about 20 ms. In some embodiments, the pulse waveform (1132) and the protection interval (1142) may begin substantially concurrently with the R-wave detection (1124).

In some embodiments, one or both of the second delay (1144) and the fourth delay (1146) can be adjustable such that the protection interval (1142) can have a duration (1148) that is adjustable.

It should be understood that the examples and illustrations in this disclosure serve exemplary purposes and departures and variations such number of electrodes, sensors, and devices, and so on can be built and deployed according to the teachings herein without departing from the scope of this invention. In particular, whether ablation energy with high voltage pulse waveforms is delivered synchronously with cardiac pacing or asynchronously (e.g., without cardiac pacing), the systems, devices, and methods disclosed herein can be configured to protect a wide variety of medical electronic equipment including but not limited to cardiac stimulators, electroanatomical mapping systems, ECG recording systems, ECG monitoring systems, device navigation or tracking systems, etc. It should be appreciated that the protection device embodiments described herein can be implemented in multi-channel formats that can protect multiple device electrodes or sets of device electrodes that may be connected to such electronic equipment. For example, the protection device can incorporate 2, 4, 6, 8, 64, 256, or 512 channels of protection. Furthermore, the control signal used for activation of the protection device(s) can be output to multiple such devices, thus providing an expandable protection device where the number of channels of protection can be expanded in modular fashion.

As used herein, the terms “about” and/or “approximately” when used in conjunction with numerical values and/or ranges generally refer to those numerical values and/or ranges near to a recited numerical value and/or range. In some instances, the terms “about” and “approximately” may mean within ±10% of the recited value. For example, in some instances, “about 100 [units]” may mean within ±10% of 100 (e.g., from 90 to 110). The terms “about” and “approximately” may be used interchangeably.

Some embodiments described herein relate to a computer storage product with a non-transitory computer-readable medium (also may be referred to as a non-transitory processor-readable medium) having instructions or computer code thereon for performing various computer-implemented operations. The computer-readable medium (or processor-readable medium) is non-transitory in the sense that it does not include transitory propagating signals per se (e.g., a propagating electromagnetic wave carrying information on a transmission medium such as space or a cable). The media and computer code (also may be referred to as code or algorithm) may be those designed and constructed for the specific purpose or purposes. Examples of non-transitory computer-readable media include, but are not limited to, magnetic storage media such as hard disks, floppy disks, and magnetic tape; optical storage media such as Compact Disc/Digital Video Discs (CD/DVDs), Compact Disc-Read Only Memories (CD-ROMs), and holographic devices; magneto-optical storage media such as optical disks; carrier wave signal processing modules; and hardware devices that are specially configured to store and execute program code, such as Application-Specific Integrated Circuits (ASICs), Programmable Logic Devices (PLDs), Read-Only Memory (ROM) and Random-Access Memory (RAM) devices. Other embodiments described herein relate to a computer program product, which may include, for example, the instructions and/or computer code disclosed herein.

The systems, devices, and/or methods described herein may be performed by software (executed on hardware), hardware, or a combination thereof. Hardware modules may include, for example, a general-purpose processor (or microprocessor or microcontroller), a field programmable gate array (FPGA), and/or an application specific integrated circuit (ASIC). Software modules (executed on hardware) may be expressed in a variety of software languages (e.g., computer code), including C, C++, Java®, Ruby, Visual Basic®, and/or other object-oriented, procedural, or other programming language and development tools. Examples of computer code include, but are not limited to, micro-code or micro-instructions, machine instructions, such as produced by a compiler, code used to produce a web service, and files containing higher-level instructions that are executed by a computer using an interpreter. Additional examples of computer code include, but are not limited to, control signals, encrypted code, and compressed code.

The specific examples and descriptions herein are exemplary in nature and embodiments may be developed by those skilled in the art based on the material taught herein without departing from the scope of the present invention. 

We claim:
 1. A system, comprising: an ablation device including a set of electrodes disposable near cardiac tissue of a heart; a catheter separate from the ablation device, the catheter including a set of sensors disposable near patient anatomy spaced from the set of electrodes; a signal generator configured to generate a pulse waveform, the signal generator coupled to the set of electrodes and configured to repeatedly deliver the pulse waveform to the set of electrodes, the set of electrodes, in response to each delivery of the pulse waveform, configured to generate a pulsed electric field to ablate the cardiac tissue and to induce voltages and currents in the set of sensors; a protection circuit configured to selectively couple and decouple an electronic device to and from the set of the sensors, the protection circuit configured to transition between a closed-circuit configuration in which the set of sensors are coupled to the electronic device and an open-circuit configuration in which the set of sensors are decoupled from the electronic device; and a processor coupled to the protection circuit, the processor configured to control the protection circuit to transition from the closed-circuit configuration to the open-circuit configuration during an interval of time beginning before and ending after each delivery of the pulse waveform to the set of electrodes to isolate the electronic device from the voltages and the currents induced in the set of sensors in response to each delivery of the pulse waveform, wherein the protection circuit includes a set of switches configured to switch between a conducting state in which the electronic device is coupled to the set of sensors and a non-conducting state in which the electronic device is decoupled from the set of sensors, wherein the set of switches is a first set of switches, and the interval of time beginning before and ending after each delivery of the pulse waveform to the set of electrodes is a first interval, the protection circuit further including: a third set of switches configured to selectively couple and decouple a set of channels associated with the set of the sensors to and from a common node, the processor further configured to control the third set of switches to couple the set of channels to the common node during a second interval of time beginning before and ending after each delivery of the pulse waveform to the set of electrodes, wherein the second interval begins before and ends after the first interval.
 2. The system of claim 1, further comprising the electronic device, the electronic device including at least one of: an electroanatomical mapping system configured to generate a map of cardiac electrical activity; a device tracking and navigation system configured to generate an anatomical map of a cardiac chamber; or an electrocardiogram (ECG) system configured to monitor cardiac electrical activity.
 3. The system of claim 1, further comprising a signal detector configured to detect an R-wave associated with each cardiac cycle from a set of cardiac cycles, the signal generator configured to deliver the pulse waveform during each cardiac cycle from the set of cardiac cycles after detection of the R-wave of that cardiac cycle.
 4. The system of claim 3, wherein the signal generator is configured to deliver the pulse waveform spaced from the R-wave of each cardiac cycle from the set of cardiac cycles by a time delay, the time delay enabling the electronic device to be decoupled from the set of sensors before delivery of the pulse waveform.
 5. The system of claim 3, wherein the processor is further configured to: receive trigger signals from the signal detector, each trigger signal indicating when the R-wave has been detected, the processor configured to control the protection circuit to transition into the open-circuit configuration in response to receiving each trigger signal, and the processor configured to control the protection circuit to transition into the closed-circuit configuration after each delivery of the pulse waveform.
 6. The system of claim 1, wherein the set of switches includes one or more relay switches or metal-oxide semiconductor field-effect transistor (MOSFET) switches.
 7. The system of claim 1, wherein the protection circuit further includes: a second set of switches configured to be in a conducting state when the protection circuit is powered off and a non-conducting state when the protection circuit is powered on, each of the second set of switches being arranged in parallel to one of the first set of switches such that the electronic device is coupled to the set of sensors when the protection circuit is powered off.
 8. The system of claim 1, wherein the protection circuit further includes one or more of: a common mode choke, a differential mode choke, or a filter circuit.
 9. The system of claim 1, wherein the protection circuit further includes at least (i) one or more capacitors, or (ii) switched-in resistors configured to absorb energy associated with the set of switches switching between the conducting state and the non-conducting state.
 10. The system of claim 1, wherein the protection circuit further includes a fourth switch configured to selectively couple and decouple the common node to an earth ground, the processor further configured to control the fourth switch to couple the common node to the earth ground during a third interval of time beginning before and ending after each delivery of the pulse waveform to the set of electrodes.
 11. The system of claim 10, wherein the third interval is equal to at least one of the first interval or the second interval.
 12. A system, comprising: an ablation device including a set of electrodes disposable near cardiac tissue of a heart; a signal generator configured to generate a pulse waveform, the signal generator coupled to the set of electrodes and configured to repeatedly deliver the pulse waveform to the set of electrodes, the set of electrodes, in response to each delivery of the pulse waveform, configured to generate a pulsed electric field to ablate the cardiac tissue and to induce voltages and currents in a set of sensors disposed near the ablation device; a protection circuit configured to selectively couple and decouple an electronic device to and from the set of the sensors while the signal generator remains coupled to the set of electrodes, the protection circuit configured to transition between a closed-circuit configuration in which the set of sensors are coupled to the electronic device and an open-circuit configuration in which the set of sensors are decoupled from the electronic device; and a processor coupled to the protection circuit, the processor configured to control the protection circuit to transition from the closed-circuit configuration to the open-circuit configuration during an interval of time beginning before and ending after each delivery of the pulse waveform to the set of electrodes to isolate the electronic device from the voltages and the currents induced in the set of sensors in response to each delivery of the pulse waveform, wherein the protection circuit includes a set of switches configured to switch between a conducting state in which the electronic device is coupled to the set of sensors and a non-conducting state in which the electronic device is decoupled from the set of sensors, wherein the set of switches is a first set of switches, and the interval of time beginning before and ending after each delivery of the pulse waveform to the set of electrodes is a first interval, the protection circuit further including: a third set of switches configured to selectively couple and decouple a set of channels associated with the set of the sensors to and from a common node, the processor further configured to control the third set of switches to couple the set of channels to the common node during a second interval of time beginning before and ending after each delivery of the pulse waveform to the set of electrodes, wherein the protection circuit further includes a fourth switch configured to selectively couple and decouple the common node to an earth ground, the processor further configured to control the fourth switch to couple the common node to the earth ground during a third interval of time beginning before and ending after each delivery of the pulse waveform to the set of electrodes.
 13. The system of claim 12, wherein the set of switches includes one or more relay switches or metal-oxide semiconductor field-effect transistor (MOSFET) switches.
 14. The system of claim 12, wherein the protection circuit further includes: a second set of switches configured to be in a conducting state when the protection circuit is powered off and a non-conducting state when the protection circuit is powered on, each of the second set of switches being arranged in parallel to one of the first set of switches such that the electronic device is coupled to the set of sensors when the protection circuit is powered off.
 15. The system of claim 12, wherein the protection circuit further includes one or more of: a common mode choke, a differential mode choke, or a filter circuit.
 16. The system of claim 12, wherein the protection circuit further includes at least (i) one or more capacitors, or (ii) switched-in resistors configured to absorb energy associated with the set of switches switching between the conducting state and the non-conducting state.
 17. A system, comprising: an ablation device including a set of electrodes disposable near cardiac tissue of a heart; a signal generator configured to generate a pulse waveform, the signal generator coupled to the set of electrodes and configured to repeatedly deliver the pulse waveform to the set of electrodes, the set of electrodes, in response to each delivery of the pulse waveform, configured to generate a pulsed electric field to ablate the cardiac tissue and to induce voltages and currents in a set of sensors disposed near the ablation device; a protection circuit including (1) a first set of switches configured to selectively couple and decouple an electronic device to and from a set of channels associated with the set of the sensors and (2) a second set of switches configured to selectively couple and decouple the set of channels to and from a common node; and a processor coupled to the protection circuit, the processor configured to: control the second set of switches to couple the set of channels to the common node during a first interval of time beginning before and ending after each delivery of the pulse waveform to the set of electrodes; and control the first set of switches to decouple the electronic device from the set of channels during a second interval of time beginning before and ending after each delivery of the pulse waveform to the set of electrodes to isolate the electronic device from the voltages and the currents induced in the set of sensors in response to each delivery of the pulse waveform, wherein the second interval begins before and ends after the first interval.
 18. The system of claim 17, wherein the protection circuit further includes a third switch configured to selectively couple and decouple the common node to an earth ground, the processor further configured to control the third switch to couple the common node to the earth ground during a third interval of time beginning before and ending after each delivery of the pulse waveform to the set of electrodes.
 19. The system of claim 18, wherein the second interval begins before and ends after the first interval, and the third interval is equal to the second interval.
 20. The system of claim 18, wherein the second interval begins before and ends after the first interval, and the third interval is equal to the first interval.
 21. The system of claim 18, wherein the protection circuit further includes a set of resistors each coupled in series with one of the second set of switches.
 22. The system of claim 17, further comprising at least one of: a first inductance filter coupled between the signal generator and a ground, or a second inductance filter coupled between the protection device and the ground.
 23. The system of claim 17, wherein the first and second sets of switches includes one or more relay switches or metal-oxide semiconductor field-effect transistor (MOSFET) switches. 